The present invention relates generally to voltage regulators, and more particularly to a voltage regulator that compensates for temperature, power supply and process variations.
It is necessary in a variety of diverse circuits to provide a regulated voltage at a given point in a circuit, which voltage does not vary despite temperature fluctuations, and voltage fluctuations in the power supply and the ground potential. In a number of applications the circuit that is to provide the regulated voltage must do so while sinking current.
Additionally, it has been discovered that in many applications it is especially critical to control and prevent the voltage supply from dropping below a given threshold voltage. In particular, it has been discovered that the most positive UP or high logic level for driver output lines and other line voltages occurs when the voltage supply drops to its lowest voltage level.
The present invention as claimed is directed to providing a regulated voltage despite temperature and power supply fluctuations, while at the same time sinking current. The invention is particularly directed to preventing the regulated voltage from dropping below a predetermined threshold. This regulated voltage is achieved without using PNP transistors.
The present invention is especially advantageous for controlling the most positive UP level for driver and other line voltage determining circuits. Accordingly, line switching pedestals within threshold regions reducing switching delays and the likelihood of false switching.